Similar symptoms make the differential diagnosis of anorexia nervosa and Addison's disease difficult at times: vomiting, weight loss, hypotension, depressed mood, reduced drive, and increased irritability can occur in both disorders. Psychological factors are then frequently presumed to be causative, so that the diagnosis of Addison's disease is made only years after the onset of the disease. Against this background, our case report presents important differential features, particularly with regard to consultative psychiatry.